The invention relates to a delivery system for flat material, in particular sheet paper, with a guideway and at least two glide elements extending in the direction of conveyance, whose surface opposite the guideway is elevated.
A delivery system is disclosed in DE-90 02 392.7 U1. According to the subject matter of this DE disclosure, ribbed projections are provided on a guideway, as a result of which sheets to be delivered slide on these projections until they reach their defined final position. The danger exists in this connection that the first sheet to be delivered will not reach its final position if it misslides. A slanting position may arise if the sheet to be delivered misslides to one side.
The object of the invention is to make available a delivery system with which a flat material can be conveyed safely into a defined delivery position.
The object is solved in accordance with the invention in that the surfaces of the glide elements opposite the surface of the guideway exhibit substantially reduced friction vis-à-vis the flat material.
The advantage of the invention lies in the fact that easy sliding on the surface of the glide elements up to the defined delivery position is assured. Further advantages are obtained through expedient refinements.
One particularly expedient refinement provides that the guideway is a delivery table and that an increased friction of the guideway surface and the height differential of this surface to the surface of the glide elements are dimensioned in such a way that a flat material, upon completion of its conveyance, deposits itself non-slippably on the surface of the guideway. By virtue of this refinement, the flat material slides on the surface of the glide elements until it comes to rest and then, overcoming the height differential, deposits itself on the surface of the guideway whose increased friction ensures that slippage of the delivered flat material and, accordingly, other flat materials being stacked into a pile on the first material delivered, is no longer possible. The higher the stack, the greater the resulting bearing pressure, and secure stack position is thereby assured.
One expedient refinement provides that the glide elements are constructed as strips glued to the surface of the guideway. As a result thereof, the glide elements are substantially easier and more economical to produce than is the case with the state of the art cited at the outset because there they are incorporated into the delivery table. The construction as glued-on strips also offers the advantage that the glide elements can be made from a material other than that of the guideway, for example, from plastic which, vis-à-vis the flat material to be delivered, exhibits lower friction than that, for example, of the metal of the delivery table. It has been shown that the glide elements are expediently made of polytetrafluoroethylene, commonly referred to as Teflon(copyright).
Conveyance of the material to be delivered can occur in different ways. Conveyance is possible by the upstream machine or a conveyance and positioning device can be provided. Good interaction with the glide elements in accordance with the invention is given if conveyor rollers with high friction surfaces and a control mechanism are provided which convey the flat material in a predetermined manner. The flat material is expediently delivered by conveyor rollers in a defined manner by conveying it to its delivery position. The above-described effect can be achieved if, during conveyance, the flat material slides on the glide elements and after conveyance has come to a stop, delivery occurs on the surface of the glide elements with increased friction.
The final position of the flat material and, accordingly, the defined delivery position can be achieved either by the above-mentioned conveyor rollers or it is possible for defined delivery to occur by a stop at the end of the guideway. Of course, both steps can also be combined together. A further measure to achieve defined delivery in combination with the steps already proposed or acting by itself can include providing a surface with increased friction in the back area of the delivery table. This surface is preferably provided at least at the height of the gliding element surface. As a result thereof, the flat material deposits itself with its back area on this surface with increased friction, whereby first its movement is absorbed and thereafter protection against shifting is achieved. The surface with increased friction also is expediently formed by a glued-on strip. Rubber has shown itself to be an advantageous material in this connection.
In order to ensure that the flat material is conveyed over the surface with increased friction, tongues can be provided by which the flat material slides over the surface with increased friction and which after delivery of the material can be withdrawn from the delivery area. It is also possible in this connection for the tongues to completely or partially cover the surface with increased friction. At the same time, this surface with increased friction and the tongues can act together with the conveyor rollers and, if necessary, even with a hold-down clamp to ensure positioning of the material so that the flat material first reaches the defined delivery position and then is securely positioned.